Leveling means or mechanism for road surfacing machines



Del3, 1949 A. s. MILLIKIN 2,491,275

LEVELING MEANS 0R MECHANISM h FOR ROAD SURFACING MACHINES F;1ed Sept. 26, 1945 3 Sheets-Sheet 1 n INVENTOR.

B Y M ,3%7 #M y Arm/:NHS

Dec. 13, 1949 A. s. MILLIKIN 2,491,275

LEVELING MEANS OR MECHANISM FOR ROAD SURFACING- MACHINES Filed sept. 2e, 1945 s sheets-sheet 2 A TTORNEYS DeC- 13, 1949 Y A. s. MlLLlKlN LEVELING MEANS 0R MECHANISM FOR ROAD SURFAGING MACHINES 3 Sheets-Sheet 3 Filed Sept. 26, 1945 I N VEN TOR.

Patented Dec. 13, 1949 LEVELING MEANS OR MECHANISM FOR ROAD SURFACING MACHINES Arnold S. Millikin, Columbus, Ohio, assigner to The Jaeger Machine Company, Ohio, a company of Ohio Columbus,

Application September 26, 1945, Serial No. 618,672

16 Claims.

The present invention relates to leveling means or mechanism for road surfacing machines. It has to do particularly, although not exclusively, with transverse leveling means or mechanism which may be mounted upon or attached to the leveling and finishing unit or assembly which includes a screed, or compactor, of a road surfacing or re-surfacing machine such, for example, as a bituminous paver.

In re-surfacing bituminous roads, it is often desirable, where the center line is reasonably accurate and true, to grade and thus correct the outside edge of the road which may be rough and in most instances, low. In re-surfacing old roads, where it is desired to increase or decrease the transverse elevation, it is desirable to perform this operation by mechanical means which may be controlled electrically, so as to automatically produce or accomplish the desired result,

When a bituminous paver, for example, is employed to carry out the aforementioned operation, it is preferable to carry or provide a uniform thickness on one end of the screed of the leveling and finishing unit and a variable thickness on the other end of the screed. In accordance with the present invention, this is effectively and accurately accomplished preferably by means of an electrically operated unit in accordance with the present invention which functions to raise and/ or lower the screed on the end thereof where the variable thickness is to occur. In accordance with the present invention, the electrically operated unit, which preferably controls the electric screed lift motor at the end of the screed where said variable thickness is to occur consists, preferably, of a pair of normally open electric switches which, when actuated, cause the operation of the electric motor for raising or lowering the end portion of the screed. These normally open electric switches are preferably operated by a switch actuating member which may be in the form of a pendulum-like member having a portion which is interposed between the lmovable contacts or actuators whenever the screed changes position relative t0 the horizontal. It will be understood that the electric motors are so positioned and arranged that when the screed moves into a position at an angle to the horizontal, the

pendulum-like member actuates one or the otherV of the switches to raise or lower the screed in the desired direction and the desired amount, The leveling means or mechanism is preferably mounted upon the screed assembly with the pendulum-like memberv having its pivot fixed relative to the screedl and with the pair of switches,

2 constituting the switch assembly being adjustabl in a horizontal, or substantially horizontal plane relative to the pendulum-like members pivot point. In accordance with the present invention certain manually controlled means is preferably provided for moving the switch assembly or unit relatively to the said pivot point. An indicating finger or hand is preferably carried by the switch assembly and is adapted to register or align with a graduated scale which is preferably calibrated to indicate the amount of screed angularity relative to the horizontal, in inches.

One of the objects of the present invention is to provide improved automatically operated mechanical means which may be electrically controlled, for use with a leveling and finishing unit of a road surfacing machine, for automatically maintaining the screed at a' predetermined level and in a predetermined position to thereby produce and maintain the desired transverse elevan tion or grade of the newly laid material.

Another object of the invention is to provide means in accordance with the preceding paragraph which is capable of manual adjustment to effect the control 0r position of the screed to increase or decrease the transverse elevation of the newly laid surface.

A further object of the present invention is to provide improved means or mechanism rof the foregoing character which is capable of being quickly and easily applied to the screed unit or assembly of a road surfacing machine, such as a bituminous paver; it being another object of the invention to provide improved transverse leveling means or mechanism which is of relatively simple construction involving but few and relatively inexpensive parts or elements.

Another object of the invention is t0 provide improved control means for the screed of the leveling and finishing unit of a road surfacing machine which functions to raise or lower one end portion of the screed in accordance with variations in the old road surface which are encountered by the forward portion, such as'tlie material receiving and feeding unit of the machine, and improved transverse leveling means or mechanism which functions to raise or lower the opposite end portion of the screed when said screed portion encounters variations in the desired transverse elevation of the newly laid material or surface; it being a further and imporn tantk object of the present invention to provide control means andtransverse leveling means which may be connected or assocatedwith either or both ends of the screed so that irregularities encountered either by the forward portion of the machine or the screed thereof, will be reiiected in the up and down movement or shifting of either end portion of the screed, dependent upon Which end portion is associated with either the control means or the transverse leveling means.

A further object .of the invention is to provide improved automatically operable transverse leveling means or mechanism which may be associated with one or both end portions of a screed so as to effect the desired raising or lowering of either or both ends of the screed; it being a further object of the invention to provide relatively simple and effective electrical connecting means for plugging in the control means or the transverse leveling means referred to in the preceding paragraph, so as to effect the desired up and down movement of the 'screed in accordance with the particular requirements of the surfacing or re-surfacing job which is being performed by the machine; it being another object of the invention to provide an elongated runner at eitherside of the machine in contact with and adapted to be moved Vover the old road surfacecr on the surface of the first half of the `newly laidmaterial, said runner being operatively associated with the screed elevator means at one end-of the screed so as to govern or control the up and down adjusting movement of the Ascreed at said end.

The foregoing and other objects and advantages of the invention will -appear from the following description and appended claims when considered-in connection with the accompanying drawings forming a part of this specication lwherein like reference characters designate simila;` parts in the several views.

In said drawings:

Figure 1 is a perspective view 'of a machine embodying my invention.

Figure 1a -is an lenlarged perspective view of a portion of the screed level controlling mechanism of the machine.

Fig.2 is a left side elevational view of a machine ior apparatus embodying the present invention.

Fig. 3 is a rear elevational view of the structure shownin Fig. 2.

Fig. l -is an enlarged elevational view vof the electric-al `switch unit or assembly of the `present invention.

Fig. 5 is an enlarged fragmentary rig-ht side elevation of the leveling and `finishing unit and associated parts embodying the present invention.

Fig. v6 is aperspective view of the switch unit or assembly of Figs. -2 to 5, inclusive; and

Fig. 'gis a diagrammatic view of an electrical circuit for electrically connecting together the switch unit or assembly, the control means and the electrically operable elevator means of the structure 'embodying the present invention.

example, a road finishing Vmachine or apparatus 4 embodying the present invention. The structure embodying said invention is shown in association with the leveling and finishing unit of one type of road surfacing machine.

Referring now to the drawings and particularly to Figs. 1 to 5, inclusive, thereof, one type of machine or apparatus forsurfaci-ng roads to which the present invention is applicable, is shown as a whole at IB. As shown, it comprises a material receiving and feeding unit, shown as a whole at I I and a following leveling and iinishing unit, shown as a whole at I2. The levelring and finishing unit is drawn along behind the material receiving and feeding unit.

The machine or apparatus I is carried by a pair 'of relatively long endless traction umts I3, one such being shown. These traction units or members "will pass over small irregularities of the sub-grade or old road surface without causing any appreciable vertical movement of the unit II.

The leveling and nishing unit I2 comprises a screed I which may be of any suitable type and may also include a following cut-off 4bar or compactor I5 (Fig. 5). The leveling andfn-ishing unit is mounted upon frame work yincluding transverse frame members I6 and upright frame members I7, see Fig. 3.

The machine I0 is provided with-longitudinal side frame members lI8 which, as shown, are fastened at I (Fig. V2.) to the upright frame members Il'. Each frame member I8 carries a runner 2), see particularly Fig.2, which is pivotally mounted at V23 for oscillating or rocking movement relative to the frame member I8. The forward end of the runner -2D lis also connected to the frame member IIS by a .pin and `slot -connection, shown at 9. Thus, when the traction members I3 are driven, the material level-ing and finishing unit I2 will be drawn along behind the material receiving and feeding unit H.

The frame structure also comprises ya pair of transverse frame members -2I (Figs. l and -3') which carry an electric motor -2-2 drivingly connected to a drive shaft 23 which serves to oscillate the cut-oilE bar or compacter I5 by-suitable means (not shown). Moreover, -the upright frame members I'! carry lmea-ns for supporti-ng and raising and lowering the leveling and `nishing unit I2. -As shown, such supporting means comprises a vertically Vextending screw threaded shaft 24, one such being located Vbetween each pair of the upright frame lmembers I1. The lower ends of 'the rods or shafts 2G fear-ry hanger blocks 25, see particularly Figs. -1, l3 and 5. The leveling and finishing `unit I2 `is in turn supported and carried adjacent-fits opposite ends `by these hanger blocks.

'Carried by and adjacent opposite ends of the transverse frame members IS'are electric-motors 2S to eachof which -is attached, indriving relationship, gear reduction mechanism within afgear box 2l. It will be understood that the gears within the boxes 2l `are ldriven bythe motorshaft in each instance. The gear reductionmechanism includes a depending upright `drivir'ig shaft 28 which carries at 'its lower end `a sprocket A29. The upper end of eachrshaft 24carri'eslaisprocket es which is driven Snom the sprocket zef'tnreugh the medium of a sprocket chain 3ft As `'clearly seen in Fig. 3, a power-operable uit' 5consisting of the electric motor, gear reductionv mechanism, driving 'and driven sprockets and 'chain is 11ocated adjacent-each fend of the frame members I8.' The motor 26 at the left of Fig. 3 is shown 'connected by a conduit or cable 32 to an electric pendulum-operated switch unit or assembly S to be described below, whereas the electric motor 26 at the right side of Fig. 3 is shown connected by a conduit or cable 32a to another and separate electric switch unit SS also to be described below. It will be understood that each of the motors 26 is preferably of the reversible type so as to drive the driving sprocket 29 and its associated driven sprocket 30 and chain 3l in opposite directions. When the electric motor 26 at the right of Fig. 3 is driven, the leveling and finishing unit i2 will be raised or lowered at its right end, dependent upon the direction in which the electric motor is running. With the parts connected as they are shown in Fig. 3, the electric motor 26 at the right of this figure is under the control of the switch unit SS at the right, the electric motor 26 at the left of this figure being under the control of the electric pendulum-actuated switch unit S. It will be seen in this figure that a second switch unit SS is associated with the transverse frame member 2| in the vicinity of its left end and that this switch unit is provided with a conduit or cable 32h, which may, if desired, be plugged into the electric motor 26 at the left side of Fig. 3 when conduit 32 is disconnected therefrom so as to place this electric motor under the control of the second-named switch unit SS at the left. With both electric motors being electrically connected with the two switch units SS and with switch S being disconnected from such motors, the leveling and finishing unit l2 may be rapidly and easily raised or lowered relative to the newly laid material N under the control of switch units SS. This is an alternative arrangement of connecting the motors and switch units or assemblies from that in which one of the motors is connected with the right hand or left hand switch unit SS and the other motor with the substantially centrally disposed switch unit or assembly S. Thus, it will be seen, that electrically operable means for raising and lowering the leveling and finishing unit l2 is carried by the frame work above said unit.

Each of the switch units SS is actuated through the medium of a longitudinally and rearwardly extending control bar or member 35, shown best in Figs. 1, 2 and 5 which is located adjacent a side of the machine or apparatus. The forward end portion of each bar or member 35 is down-turned and pivotally or oscillatably connected to the pivot 8 at the inside of the runner 20. The member 35 extends rearwardly beneath the transverse vframe members I6 and terminates in a rear vdown-turned end portion 35a. This end portion is pivotally attached to an arm 36a which forms a part of a leveling pan or runner attaching assembly, shown as a whole at 3B, which assembly is suitably mounted upon the rear portion of the screed I4.

In the present instance, by way of example, the assembly 36 includes a rockable cross shaft 35h to which the inner end of the arm 36a is connected by a normally fixed but adjustable connection. The shaft 36h may carry, by a normally fixed but adjustable connection, at either or both of its outer ends a rearwardly extending arm 36e whose rear end portion is pivotally or swingably connected to a bracket or bearing 60a (Figs. 1 and 5) carried by an elongated auxiliary runner 60 preferably of angle iron or L-shaped 'cross section. The bracket 60a and armA connection are'preferably located at a point midway between the front and rear ends of the runner 60. The shaft 36h also carries a normally fixed but adjustable rearwardly extending arm 36d which preferably has a down-turned rear end portion upon which is rigidly mounted a leveling pan or member 36e. As seen in Fig. 5, the pan 36e may be held in raised position and out of contact with the newly laid surface N. In accordance with the showing in this figure, the pan 36e is not being used in the operation of the road surfacing machine but in lieu thereof, the elongated runner 60 is in operative connection with the cross shaft 36h and is resting upon the old road surface R adjacent one edge of the newly laid material N.

As clearly seen in Figs. 1, 2 and 5, the runner 60 is provided with a slotted bracket 6| which serves as means for mounting the runner upon the side framework of the machine to permit its limited up and down movement. A similar bracket @la is carried by the runner 60 adjacent the forward end of the machine, this bracket being suitably and slidably connected to the longitudinal side frame member i8. The forward end of the runner 60 is also connected at t2 to the frame member i8 adjacent the forward end thereof, by means of a link or swingable connecting member 63. The auxiliary elongated runner G is so attached to the machine that it will follow a course parallel to the machine and be free to move vertically independent of the machine for a distance of several inches. The runner 6c is arranged to travel on the old road surface R (Fig. 5). It may be used, as shown, without the leveling pan 36e at the adjacent side of the screed I4, cr, if desired, it may be used in conjunction with said leveling pan, with the latter traveling on the newly laid surface N. The auxiliary runner Si! is so mounted upon the machine that when the screed I4 is elevated out of contact with the surface when the machine is not in operation but is traveling, it will be raised with the screed to clear the surface. For this purpose, a pair of chains 64 and 65 may be provided, see Fig. 5.

Associated with each of the arms 35 and the switch assemblies SS is an adjustable coupling unit, shown as a whole at 3l. The attaching assembly 3l is used to connect or attach the auxiliary runner @El with the apparatus, or to support the leveling pan 3de in operative position, or to support both the auxiliary runner 6! and the leveling pan 35e in operative positions for simultaneousruse. In other words, in accordance with the present invention, the auxiliary runner 65 Ymay be employed as a part of the leveling mechanism, or the leveling pan 36e may be so employed in lieu of the use of the runner; or, as suggested above, both the runner 66 and the leveling pan Ste may be employed together to per-form the desired leveling function. Moreover, if desired, an additional leveling pan Ste may be employed at the opposite side of the apparatus in conjunction with either the runner 60 or the right hand leveling pan 36e, or in conjunction with both of the latter. Furthermore, while the runner Sil has been shown as positioned at the right side of the apparatus, it is to be understood that if they occasion arises, this runner or a similar runner may be supported at the left side of the apparatus. If desirable, runners, such as the runner Bil, may be used on both sidesv of the machine and without employing the transverse 7 legging' unit or assembly, indi-cated as awhole .a

It `is to be understood that the vrunner 6l is preferably employed, in lieu oi one or-.more of the leveling pans 36e, -or in conjunction with one or more of said pans, when it is .desirable Vtc provide a more accurate :surface along the center lineof the road.

The 4switch mechanism or unit SS, :shownfat thefright end of Fig. 3 serves to control the elevation yor grade .ci the newly laid material at the right `end of the screed and .functions 'to actuate the 'electric .motor and .screedl elevator atn that -fen'd toraise -or lower this .end .of the :screed in accordance with .any-variationsinthe grade level.

twi-ll be understood that hydraulically actuated elevator means maybe employed in place of. the electric lift motors 26 ,forzraising and/:or lowering the :screed I4. Moreover, it. may be desirable to employ a double acting hydraulic valve in place oi each of the snap-:actionmechan-isms :or unitsY SS. In this case, the .screed would be :actuated to effect `the desired leveling Aby hydraulic means such, for example, Aas that disclosed in the patent to Millikin and Pickard No. 2,295,519 ,patented .September 8, V-1'92 instead foi .by the electrical means described and `shown herein.

For the purpose of maintaining a constant transverse Agrade level of the newly :laid .material, improved .transverse leveling means or mechanism in the -form of the pendulum-actuated switch u-nit or assembly s, is provided. As seen in Figs. 1 and 3, an auxiliary fra-me, .shown .as a whole at 4D, is mounted yupon the screed frame members 2l vand serves to support the switch unit or mechanism S.. As shown, the ,switch assembly comprises .a main frame portion 4:I and an .auxiliary and longitudinally .ad-justable .sub-frame vportion 62. The sub-.frame .nortion 42- carries -a pair of Yopposed .normally open snap-action switches i3 vand ,44 Whose contact ,points or members 43a. .and .Ma .are -in :closely ,spaced .opposed relationship, .see Figs. 4k .and -6.

The fixed or main frame 4i oi the assembly .car-

ries a pendulum-like switch actuating member, shown as a whole at 45. This member comprises a depending arm Vhaving a weight at 116 a't 'its lower end and being pivotally mounted .at lll Yfor swinging movement upon .a xed 'block or member t8. .The arm extends above the pivot and has an inturned end. .portion 49 which normally lies in a position between the Opposed ,switch contact members 43a and 44a. It will be seen that when the screed I is ina 'horizontal position, with the auxiliary 'frame fl lin a likewise horizontal position, the 'arm 'of the pendulum-'like member remains in a Avertical position with its upper end portion 49 positioned between and spaced from or out of contact with'the-switch contacts 43a and 46a. The main frame member -M carries an arcuate plate 250 having algraduated scale-.5l attached to the 'face thereof. :The auxiliary ormovable frame member d'2 .of the `switch .assembly carries an indicating 'finger or :pointer `52 which vis adapted to register with .the graduations .on the scale. The auxiliary frame 42 ris, mounted `onirame 4l -by pin yand'slct connections -dla and Mb yat vboth its Lipper and 4.lower sides, as shown inFig. 4, Vmay be adjusted longitudinally with vrelation to -the main frame M .by means of a threaded shaftfandoperating `handle or wheel, shown tasa whole .at 5,3.

preferably adjusted so that the pointer registers with the desired indication .on .the graduated -scale .524, the setting .corresponding to the desired elevation which is to be achieved and Vmaintained in the newly laid road surface or material. As seen in Fig. `3, the switch assembly has been set with 'the pointer 52 registering with the .numeral l at the left of zero .(0) .on 'the graduated Scale fail. in vthis position the pendulum contact por,- tion 49 :is in .engagement with the switch contact 44a and as the result, the electric motor .2.6 .at the left end of ligure will be energized to nperate 1.the :screed velevator mechanism to .raise or .lower the screed until the desired grade level .has-heen reached. The pendulum-like member 45 remains .at all times, in its normal vertical Vposition .and does ,not move until the screed moves out of its normal horizontal position. `'33.lius.,.fas the .angle of the screed changes,v the member f45 moves and .its portion 49 engages either of the switch contacts '43a .or 44a to actuate one of the switches 43 or d4. Likewise, any tilting .or .angular movement of the lef-t end vof 4t-he screed lil from its normally set position .to maintain the desired grade level for which the `siifitch assembly -S has been set, causes movement ofv .the pendulum-like member 45 into engagement A.with one `or the other -of the Ycontacts '43a or .414e to operate vthe switch whose .Contact is engaged. This will effect the operation .of .the electric motor 2t to raise .or lower the screed until .it resumes `the normal position for which it has been set Ato maintain the desired .transverse grade .level oi the newly laid surface.

The setting of the switches inaccordance with the showing in Fig. 3 of -the vdrawings issuchzthat the elongated runner and its associated .Switch .SS and `other associated parts will tend to -main- 'tain .the grade level at they right .end .of Fig. .3

constant, while at the same time the transverse `leveling switch assembly S Vfunctions .to maintain -theftransversegrade level at the leitof the screed normally constant in accordance with the setting -of the last-named switch assembly. If desired, however, :the cable or conduit 32 may be .disconnected .from the left .hand motor -26 and the cable 32h plugged into this motor, thus connectingthe switch SS at the 4vleftJ ,with .said motor. In v that event, a leveling pan, such as the pan '36e will `be lapplied to the attaching .assembly .3B at .the lett end o f :the screed I4 and this pan, together with .the .auxiliary runner 60, or a leveling pan 36e, zasthe lcase may be, .located at the ,right Aend of the screed, will iunctiontocontrol theswitches the Aelectric motors and vthe screed elevators so .as toraise-or lower the ,entire Screedin accord- .ance with .any variation-s .in the grade `level of `the newly .laid .surface .to maintain said leyel constant. Moreover, if .,desired, a .runner 76.0 or if desired, ,a1pan 3 fic, maybe Vused at the left .end ofthe screed and .therunner 60-orpani3 Se `at the right either removed .or vmoved .out of .contact with the surface of the newly zlaid material. '.In this case, the .conduit `or cable 3217 4willbe plugged Minto the motor 25 at .the Aleft andthe ACableZ from the switch :assembly S willlbepluggedinto the electric motor 26 at the right end of Fig.

the electric switchassembly VS will control the motor andits associated elevator at the right end .of the screed while .the vswitch .assembly .SS .at .the .left ,end .of .the screed is .controlling the .motor-.V2.6 .atthat end,

The .operation -of the .mechanism ,or .apparatus .o .the invention to .accomplish the i desired level- The .switch vmechanism with V-itspointcr `52 iis,- 75 ingofthe .rnewlylaidroadsurface andiaaccordance with the arrangement of parts as illustrated, merely by way of example, in the drawings, is substantially as follows: Assuming that the outside edge of the road, namely that section of the newly laid material at the left of Fig. 3, is to be raised one (1) inch higher than the thickness of material laid at the center line, namely at the right end of Fig. 3, the end of the screed at -said center line of the road is set so as to lay the given thickness. The switch unit or assembly, S, namely the auxiliary or movable frame portion 42 thereof, is moved horizontally by turning the hand wheel 53 until the end of the screed along the outside edge of the road (at the left of Fig. 3) is raised enough by the screed lift motor 26 at that side to lay the desired thickness. From this point on, vertical movement of the machine will be reflected in movement of the pendulum actuator 45 which actuates the screed lift motor switches 43 and 44, thus raising or lowering the outside or left end of the screed to maintain the desired level. When using this system of leveling, the switch unit SS at the left of Fig. 3 and the leveling pan or runner attaching assembly 36 are disconnected from the screed lift motor 26, which controls the elevator at the left end of the screed as seen in Fig. 3, and the transverse leveling control mechanism, namely the transverse leveling switch unit S, is connected to the left side screed lift motor 28. As also explained above, the electrical circuits are so arranged that they can be changed to operate one end or the other of the screed I4 by simply disconnecting the auxiliary runner or leveling pan switch SS by pulling out the plug and substituting the plug for the transverse leveling switch unit or assembly S.

In Fig. 7 of the drawings there is illustrated a diagram of a conventional electrical circuit for connecting the snap-action switches of the switch units SS with one or both of the electric lift motors 26 and the snap-action switches 43 and 44 with either of the screed lift motors 26, in accordance with the particular job which is to be performed by the road surfacing machine or apparatus.

Having thus described my invention, what I claim is:

1. A road surfacing machine comprising a leveling and finishing unit including a screed, electrically operable elevator means carried by the leveling and finishing unit for raising and lower-- ing the screed at predetermined times, control means carried at the rear of the machine having a portion adapted to ride upon the newly laid road surface and operatively connected with the electrically operable elevator means to actuate the same for raising or lowering said screed to compensate for vertical movement of said unit caused by contact of a portion of the machine with a variation in the road surface, and separate means carried by the leveling and finishing unit for actuating the electrically operable elevator means at predetermined times when said leveling and finishing unit is tilted transversely as the machine moves along the surface over which it operates whereby to adjust the transverse elevation of said screed and thereby maintain the transverse grade level of the newly laid surface substantially constant at all times, said separate means comprising a normally open electric switch carried by said leveling and finishing unit and electrically connected to said elevator means and a switch-actuating member carried by said unit in close proximity to said switch and being 10 mounted for free movement by gravity force upon transverse tilting of said unit for closing the switch to actuate the electrically operable elevator means at predetermined times in accordance with the transverse tilting of said unit.

2. A structure according to claim 1, wherein said separate means comprises a pair of the normally open electric switches which are opposed to each other and are electrically connected to the elevator means and wherein said switchactuating member is disposed between said switches and is adapted to engage and close said switches at predetermined times in accordance with the transverse tilting of said leveling and iinishing unit.

3. Structure according to claim 1, wherein said separate means comprises a unitary switch structure carried by the leveling and finishing unit, said unitary switch structure including a pair of transversely spaced and opposed normally open electric switches electrically connected to the elevator means, and wherein said switch-actuating member is a freely pivoted pendulum having a portion disposed between the switches and swingable transversely for closing one or the other of said switches in accordance with the tilting of said unit.

4. Structure according to claim 1, wherein said separate means comprises a unitary switch structure carried by the leveling and finishing unit, said unitary switch structure including a pair of transversely spaced and opposed normally open electric switches electrically connected to the elevator means, and wherein said switch-actuating member is a freely pivoted pendulum having a portion disposed between the switches and swingable transversely for closing one or the other of said switches in accordance with the tilting of said unit and means for adjusting the unitary switch structure transversely relative to the pivot of the pendulum whereby to accommodate the said separate means to a desired increased or decreased transverse elevation of the newly laid material and to maintain said elevation substantially constant.

5. Structure according to claim 1, wherein said separate means comprises a unitary switch structure carried by the leveling and finishing unit, said switch structure including a pair of transversely spaced and opposed normally open electric switches electrically connected to the elevator means, and wherein said switch-actuating member is a freely pivoted pendulum having a portion disposed between the switches and swingable transversely for closing one or the other of said switches in accordance with the tilting of said unit, means for adjusting the unitary switch structure transversely relative to the pivot of the pendulum whereby to accommodate the said separate means to a desired increased or decreased transverse elevation of the newly laid material and to maintain said elevation substantially constant, and indicating means associated with the unitary switch structure for indicating the setting of said switch unit to obtain the desired transverse elevation of the material being laid.

6. A road surfacing machine comprising a leveling and finishing unit disposed at the trailing end of the machine, said unit including a screed, electrically operable elevator means for raising and lowering the screed at predetermined times, a normally open electric switch unit carried by said unit and electrically connected with the electrically operable elevator means for eiecting acercan the operation of said elevator means when Vthe switch is closed, and a member movably mounted on said unit and in close proximity with` the electric switch unit for closing the same at predetermined times, said movable member being mounted for free movement by gravity force created when the leveling Yand finishing unitk tilts transversely as `the machine encounters variations in thetransversegrade level of the surface over which it operates to automatically raise or lower the screed 'to adjust its transverse elevation and to thereby maintain the transversevg'rade level of the Vnewly laid surface substantially constant.

7. A structure according to claim 6, wherein the electric switch unit comprises a pair of transversely spaced normally open electric switches, and wherein said movable member comprises a pendulum disposed between the switches and having an operating arm swingable transversely into engagement with either lof said switches for closing one or the other thereof at predetermined times.k

8.A structure according'to claim 6, wherein the electric switch unit comprises a pair of transversely spaced normally open electric switches, wherein said movable means comprises-a freely swingable pendulum disposed between the switches' and having an operating arm swingable transversely into engagement with 'eitherof said switches for closing one or the other thereof 'at predetermined times, and wherein tsaldiswitches are adjustable transversely frelat'ive Ito 'said pendulum.

9. A road surfacing `machinecomprising"'a leveling and nishing unit disposed at the trailing end of the machine, said unit including a 'main frame and a subframe adjustable upand down relatively to one another anda screed 'carried by the subframe, electrically operable elevator means connected with the-main and subframe for raising and lowering the screed at predetermined times, a pair of normally open electric vs'vvimlies electrically connected with the electrically operable elevator means for effecting the operation of f said elevator means when. either ofthe switches is closed, said switches being carried by'said subframe, and a pendulum pivotally mounted on the subframe having a portion disposed between the switches for closing one or the other thereof Vat predetermined times in vaccordance withtilting movement of the finishing unitfas them-achille moves along.

10. A road surfacing machine includingfpowerdriven tractor means andk comprising a' material receiving Yand feeding unit adapted to travel over asurface to be paved, a leveling and finishing unit connected with said material receiving and feeding unit and including a screed mounted for vertical movement on said unit, elel'strically` operable elevator means for raising and lowering the screed relative to said leveling and finishing-unit, normally open electric switch means electrically connected with the elevator means for operating the same when the switch is closed, means for closing the electric switch at predetermined times to compensate for vertical movement of said leveling and finishing unit caused when 'themachine encounters variations in the old-road surface to autcmatically'raise or lower the screed of said leveling and finishing unit dependent 'upon whether or not the variation in said road surface is a raised portion or a depression, a pair of normally open electric switches carried kby the leveling and finishing unit, and a pendulum carriedby'the leveling and finishing unit for free transverse pivotal movement and having a portion disposed between the switches for closing one or the other of said switches Ato actuate the electrically operable elevator means at predetermined times when the screed is tilted transversely because of vtransverse tilting of said leveling and finishing unit as' the machine moves along rthe surface to be paved.

l11. A road surfacing machine including powerdriven tractor means and comprising a material receiving and feeding unit adapted to travel over a surface to be paved, a leveling and finishing unit including -a screed mounted for vertical movement on said material receiving and feeding unit, separate electrically operable elevator means carried by said leveling 'and lfinishing unit and connected to said screed for raising and lowering said screed relative to said unit at predetermined times, control means including an elongated surface contacting runner located at one side of the machine and cooperable with one ofsaid electrically operable elevator means for operating the same at predetermined times to raise or lower the screed as the machine encounters variations in the surface over which it travels, a pair of normally open electric switches carried bythe leveling and finishing unit, and a pendulum switch-actuating member pivotally carried by said leveling and finishing unit'for transverse swinging movement and having a portion thereof disposedY between the switches for closing one or the other of Asaid switches to actuatc the other of said electrically operable'meansfcr raising or lowering the screed at predetermined times in accordance with transverse tilting engagement of said leveling and finishing unit as the machine moves along.

12. Structure according to claim 1l, wherein the runner is detachably connected midway of its ends vwith the leveling and finishing unit and wherein said runner extends beyond the front and rear ends of said leveling and finishing unit.

-13. Transverse leveling means for application to the leveling and finishing unit of a road surfacing machine for maintaining a predetermined transverse position of the screed of said leveling and finishing unit whereby to maintain the desired transverse'grade level of a surface being laid by the machine; said leveling means comprising' electrically operable elevators disposed adjacent opposite ends of the leveling and finishing unit for raising and lowering the screed of said unit, and a unitary electric switch assembly carried by'said unit and including a pair of transversely spaced and opposed normally open electric switches, said switch assembly including' a switch operating member having a portion thereof disposed between said normally open switches and freely movable transversely by gravity force in opposite directions for closing one or the other or said-switches to actuate one of said electrically operable elevators in response to transverse tilting of said unit.

r1li. A road surfacing machine comprising a frame' supported for'movement along the surface to be covered, a transversely extending material leveling member carried by' the frame, means for supporting and adjusting said leveling member on the frame and including electrically operable means connected to said frame and to said material leveling member and adapted to be actuated tomove said leveling member to various vertical positions on the framdmeans for actuating said '75 electrically operable means to automatically change the vertical position of said leveling member on said frame as the frame moves vertically while the machine is passing along over the surface to be covered, said means comprising a control member supported by said frame 'for vertical movement relative to the leveling member and adapted to ride on a surface having a certain grade line, an electric switch carried by the machine for actuating said electrically operable means and being electrically connected thereto, means for operatively connecting said control member to said switch so that said switch will be actuated to operate said electrically operable means to move said leveling member vertically Whenever the leveling member moves vertically relative to the control member, and additional means for actuating said electrically operable means to automatically change the transverse elevation of said leveling member to maintain a predetermined transverse grade level on the surface being laid by the machine, said means including an electric switch carried by the machine and electrically connected to said electrically operable means, and a freely movable switch-operating member carried by the frame and responsive to transverse tilting of said frame for actuating said switch tc operate said electrically operable means to adjust the transverse elevation of said leveling member.

15. A road surfacing machine comprising a frame supported for movement along the surface to be covered, a transversely extending material leveling member carried by the frame, means for supporting and adjusting said leveling member on the frame and including electrically operable f.,

means connected to said frame and to said material leveling member and adapted to be actuated to move said leveling member to various vertical positions on the frame, and means for actuating said electrical operable means to automatically i change the transverse elevation of said leveling member to maintain a predetermined transverse grade level on the surface being laid by the machine, said means including an electric switch carried by the machine and electrically connected to said electrically operable means, and a freely movable switch-operating member carried by the frame and responsive to transverse tilting of said frame for actuating said switch to operate said electrically operable means to adjust the transverse elevation of said leveling member.

16. A road surfacing machine comprising a frame supported for movement along the surface to be covered, a transversely extending material leveling member carried by the frame, means for supporting and adjusting said leveling member on the frame and including adjusting means connected to said frame and to said material leveling member and adapted to be actuated to move said leveling member to various vertical positions on the frame, and means for actuating said adjusting means to automatically change the transverse elevation of said leveling member to maintain a predetermined transverse grade level on the surface being laid by the machine, said lastnamed means including a control unit operatively connected to said adjusting means, and means for actuating said control unit in response to transverse tilting of said frame and comprising an actuating member carried on said frame for free movement in accordance with transverse tilting of said frame.

ARNOLD S. MILLIKIN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Namel Date 2,054,437 Mosel Sept. 15, 1936 2,295,519 Millikin et al. Sept. 8, 1942 

